"There's a mysterious predator lurking in the depths of Australia's wild Southern Ocean, a beast that savagely devoured a great white shark in front of cinematographer David Riggs 11 years ago," the Smithsonian Channel stated. "Riggs' obsession to find the killer leads him to an aquatic battle zone that's remained hidden until now. Here, killer whales, colossal squid, and great white sharks face off in an underwater coliseum where only the fiercest creatures of the marine world survive."

"When I was first told about the data that came back from the tag that was on the shark, I was absolutely blown away," Riggs says in the video clip, referring to the strange body temperature measurements in the shark, which reportedly experienced a jump from 44.6 degrees Fahrenheit to 77.

The video quoted researchers who said the only way a shark could experience a temperature change that quick is if it was inside the belly of another animal.

"The question that not only came to my mind but everyone's mind who was involved was, 'what did that?'" Riggs says in the clip. "It was obviously eaten. What's gonna eat a shark that big? What could kill a 9-foot great white?"